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Old 13-09-2003, 03:12 PM
scyap
 
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Default Brown Spots on Leaves Killing Rose Plants

I bought some pots of roses over a period of about 4 weeks. One day I
noticed some brown spots on the leaves of one of the plants and very quickly
all the plants had brown spots. They then started shedding leaves.
Subsequently I bought a container of 'insecticide' where the label stated
that it was for brown spots in roses. However, after spraying, most of the
leaves fell off and the new leaves became knurled and very small.

I have now cut off all the branches wherever there are leaves or shoots
(leaving only the stumps) hoping that this will stop the 'epidemic'.

I am indeed very unfamiliar with caring for roses and will appreciate your
advice as to what I need to do next. Thank you.

Regards,
SC Yap



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Old 13-09-2003, 06:02 PM
Shiva
 
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Default Brown Spots on Leaves Killing Rose Plants

On Sat, 13 Sep 2003 22:08:55 +0800, "scyap"
wrote:

I bought some pots of roses over a period of about 4 weeks. One day I
noticed some brown spots on the leaves of one of the plants and very quickly
all the plants had brown spots. They then started shedding leaves.


We need more information. Where are you? Have you left these roses in
their little tiny pots, or put them in bigger pots, or in the ground?
What kind of roses are they? Most importantly, are they inside or
outside, and have you left trays under the pots (if they are in pots)
or not? If you have, your roses are drowning and rotting. If the spots
are black, your roses have the fungal disease blackspot, which causes
defoliation. In the latter case you need to spray them with a
fungicide or learn about roses that do not tend to get blackspot.



Subsequently I bought a container of 'insecticide' where the label stated
that it was for brown spots in roses. However, after spraying, most of the
leaves fell off and the new leaves became knurled and very small.



You need to do some reading. The disease is called blackspot and it is
fungal, has nothing at all to do with insects. Keeping roses alive is
not rocket science but you do need to know a few things.

1. They are outside plants
2. They must have 6 hours of sun minimum a day to do well.
3. They need lots of water but they MUST DRAIN. In pots, no trays
underneath. In the ground, after you dig the hole fill it with water.
If it takes longer than three hours to drain I would not put a rose in
there. (Others say longer.)
4. They need protection against fungal disease in some areas (some
types more than others) and sometimes, from insects.

Go googling. It is all out there.





I have now cut off all the branches wherever there are leaves or shoots
(leaving only the stumps) hoping that this will stop the 'epidemic'.

I am indeed very unfamiliar with caring for roses and will appreciate your
advice as to what I need to do next. Thank you.

Regards,
SC Yap



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Old 13-09-2003, 08:22 PM
Shiva
 
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Default Brown Spots on Leaves Killing Rose Plants

On Sat, 13 Sep 2003 12:17:26 -0500, dave weil
wrote:



However, it' probably isn't black spot since most people describing
the ailment for the first time are quick to talk about the yellowing
of the leaves (I'm just speculating though).


Indeed you is. G First thing I usually hear (or remember hearing) is
"leaves dropping." And, truth be told, lots of bs is not really black.
Black plus yellow equals brown. I win I win hahaha.



It could be one of those other "tree funguses" or it could just be the
way the leaves look when they defoliate.

Just pointing that out...

g


Ahh, pffft. It's black spot or rot from sitting in water.

But you are kinda cute when you're passive aggressive.

G

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Old 14-09-2003, 09:13 AM
scyap
 
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Default Brown Spots on Leaves Killing Rose Plants

Thank you for your information.

My garden is at the rooftop of an apartment block in the tropics ( temp
being above 30 deg C with humidity about 90%) with almost 12 hours sunlight
everyday.
The plants are in pots ( some were re-potted) and placed on wooden stands
meant for potted plants.

I had tried using the Yates Rosegun Black Spot and Insect Killer. In any
case, do you think by cutting off all the leaves and shoots off all the rose
plants that I have could put a stop on this infestation?

I shall also do a google search. Any starting leads will be appreciated.
Thank you.

Regards,
SC Yap


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Old 14-09-2003, 09:22 AM
scyap
 
Posts: n/a
Default Brown Spots on Leaves Killing Rose Plants

Thank you for your information.

My garden is at the rooftop of an apartment block in the tropics ( temp
being above 30 deg C with humidity about 90%) with almost 12 hours sunlight
everyday.
The plants are in pots ( some were re-potted) and placed on wooden stands
meant for potted plants.

I had tried using the Yates Rosegun Black Spot and Insect Killer. In any
case, do you think by cutting off all the leaves and shoots off all the rose
plants that I have could put a stop on this infestation?

I shall also do a google search. Any starting leads will be appreciated.
Thank you.

Regards,
SC Yap


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Old 14-09-2003, 05:42 PM
Shiva
 
Posts: n/a
Default Brown Spots on Leaves Killing Rose Plants

On Sun, 14 Sep 2003 15:43:03 +0800, "scyap"
wrote:

Thank you for your information.

My garden is at the rooftop of an apartment block in the tropics ( temp
being above 30 deg C with humidity about 90%) with almost 12 hours sunlight
everyday.
The plants are in pots ( some were re-potted) and placed on wooden stands
meant for potted plants.


With trays under them, right? Or saucers? You must remove the trays
from beneath them so that they drain freely, or your roses will never
be healthy.


I had tried using the Yates Rosegun Black Spot and Insect Killer. In any
case, do you think by cutting off all the leaves and shoots off all the rose
plants that I have could put a stop on this infestation?


Removing diseased leaves is always a good idea, and make sure there
are none in the soil in the pots, too, as blackspot spreads. Do not
hack your roses, though, it will only set them back. Make sure they
are draining freely, water them copiously daily, and feed them with
water soluable ferts like MiracleGro for Roses, the kind you mix in
their water, and perhaps some time release Osmocote. Potted roses need
fertilizing more often, but it is also easy to over fertilize them.
NEVER use granular three-month type fertilizer, I killed some that
way. Think frequent feedings at diluted rates. If you are feeding them
well they will replace their leaves in no time and be blooming. If you
will not let them drain freely, give them away to someone with a
garden and grow something else.

Good luck and welcome to the forum!




I shall also do a google search. Any starting leads will be appreciated.
Thank you.

Regards,
SC Yap



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Old 15-09-2003, 06:32 AM
Cass
 
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Default Brown Spots on Leaves Killing Rose Plants

In article , scyap
wrote:

Thank you for your information.

My garden is at the rooftop of an apartment block in the tropics ( temp
being above 30 deg C with humidity about 90%) with almost 12 hours sunlight
everyday.
The plants are in pots ( some were re-potted) and placed on wooden stands
meant for potted plants.

I had tried using the Yates Rosegun Black Spot and Insect Killer. In any
case, do you think by cutting off all the leaves and shoots off all the rose
plants that I have could put a stop on this infestation?

I shall also do a google search. Any starting leads will be appreciated.
Thank you.


Images of rose disease and insect infestations are found on a variety
of sites. Start with Baldo's Bugs & Roses:
http://www.sactorose.org/rosebug/index.htm

Dr. Villegas is an entomologist with the California Department of
Agriculture and an avid rosarian.

Since you garden in tropical conditions, you might take a look at the
Honolulu Rose Society website:
http://www.roseshawaii.org/

Also, browse the articles of the American Rose Society at
http://www.ars.org/explore.cfm/articles/


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